1. Field of the Invention
The present invention relates to an apparatus and a method of manufacturing a stator core of a vehicle ac generator and, particularly, a spirally wound stator core of a magnetic steel strip.
2. Description of the Related Art
JP-A-1-164247 disclosed a pair of forming rollers for pressing a magnetic strip in an inclining, thereby thinning the magnetic strips toward one side thereof, thereby forming a spirally piled core.
JP-B2-38-7402 discloses an apparatus for manufacturing a stator core comprising a pair of tapering rollers providing a wedge-shaped space therebetween. A magnetic steel strip is inserted in the space to press-form a spirally piled core.
Because the magnetic steel strip is moved by means of a friction force of the steel strip with the forming roller in any one of the above disclosed apparatuses, it is difficult to prevent the steel strip from slipping on the forming rollers. This occasionally varies thickness of the steel strip and, therefore, the radius of the spiral.
U.S. Pat. No. 4,116,033 or its corresponding Japanese Patent JP-B2-59-36503 discloses an apparatus having a rotatable disk with a plurality of pins fixed thereto, which engage with slots of a magnetic strip to form the strip into a spirally piled core.
Because the number of pins are fixed according to the number of the core slots, it is necessary to change the rotatable disk if a stator core has different number of the core slots.